JPH02166367A - Temperature expansion valve - Google Patents

Abstract

PURPOSE:To make it possible to send refrigerant to an evaporator even when its degree of superheat is small by giving an additional power to a valve disk pushing power based on a superheat signal and an amount of diaphragm deflection when a differential pressure between the upper stream side and the lower stream side of refrigerant is larger than a reference differential pressure which sets a superheat degree at a rest. CONSTITUTION:When a liquid flows at a pressure higher than a certain differential pressure against the power of a power element which affects the opening/ closing of a valve, the size of a valve port 10 is made sufficiently larger in terms of an effective size of a diaphragm 2 of a power element so that the valve may be opened, and a valve disk is designed to be a cone-shaped valve so that the power produced by the flow of a fluid may be taken out effectively, then the apex angle of the cone is determined. Therefore, when the vaporization temperature or the vaporization pressure is lower as a result of deviation from the superheat characteristics a standard state valve lift (valve opening area), the valve can be opened even with a superheat degree signal which has not reached the degree of statical superheat and refrigerant is supplied to an evaporator.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method of controlling a refrigeration system using a temperature expansion valve used in a refrigeration cycle, in particular a method for controlling a refrigerant to flow into an evaporator in its low evaporation temperature range. The present invention relates to a structure of a thermal expansion valve suitable for use in a thermal expansion valve.

[Conventional technology]

The first typical configuration of a refrigeration system used for air conditioning is
As shown in FIG. 3, the high temperature refrigerant gas compressed by the compressor 207 is liquefied by exchanging heat with the outside world in the condenser 208, and then sent to the liquid receiver 209.
After that, the pressure is reduced by the temperature expansion valve 201, and the gas is gasified by exchanging heat with the outside world in the evaporator 205, and then returned to the compressor 207 again.

The temperature expansion valve 201 has the function of reducing the pressure of high-pressure liquid refrigerant to make it easier to evaporate before sending it to the evaporator. The amount of refrigerant supplied is controlled by using the signal (call) as a signal.

The basic operation of a thermal expansion valve is to open and close when the above-mentioned degree of superheat differs from the preset static superheat degree, and the purpose is to send refrigerant to the evaporator so that a constant operating degree of superheat is maintained. This is feedback control.

Conventionally, in refrigerators, when the heat load on the evaporator is small, the superheat degree signal is small, and the temperature expansion valve does not open and evaporation occurs because the static superheat level set by the temperature expansion valve is reached. No refrigerant is supplied to the device.

This also served the purpose of protecting the compressor, since it would be dangerous if the refrigerant flowing into the evaporator returned to the compressor in a liquid state without sufficient heat exchange. However, on the other hand, there are also demands that are exactly the opposite of the above. In other words, when the evaporation pressure (and therefore the evaporation temperature) is low, even if the superheat signal is small, the refrigeration system is installed so that the thermal expansion valve remains open and refrigerant liquid is pumped into the evaporator. It is a request to do so. An example of this is the following passage.

■ Evaporation pressure - To prevent the evaporator from freezing when the evaporation temperature is low, more refrigerant is pumped into the evaporator than necessary to turn the evaporator into a droplet state.

■ When using a variable capacity compressor (one that senses the evaporation pressure and controls the compressor capacity when the evaporation pressure is low), the heat load becomes small and the temperature expansion valve function closes. Since the evaporation pressure signal to the variable capacity compressor becomes unstable, the refrigerant should instead flow to the evaporator.

The above requirements are undesirable properties for conventional thermal expansion valves, and are difficult to achieve with conventional thermal expansion valves alone. cannot be reached.

Among the technical ideas conventionally used to achieve the above object, a simple method is to provide a notch or a tree port in the valve seat. In this method, a passage is created in parallel with the thermal expansion valve to allow a constant flow rate (a function of the pressure difference) of refrigerant to flow, so that a constant amount of refrigerant flows even when the thermal expansion valve is closed.

This method has the disadvantage that the temperature expansion valve cannot fully demonstrate its ability because it causes an amount of refrigerant unrelated to the control to flow even in the area where the temperature expansion valve is supposed to function.

In fact, this method often fails to satisfy the above objectives. There is also a configuration in which a constant pressure expansion valve function is added, and when the evaporation pressure falls below a constant pressure, the valve opening degree is controlled by the constant pressure expansion valve regardless of the control signal for the temperature expansion valve.

An example of this is disclosed in Japanese Utility Model Application No. 61-153875.

This idea is based on the first control drive unit A (coded 26°27.25,
This is a method using an expansion valve having two valve opening control parts: a second control drive part B (consisting of reference numerals 21 and 22) which acts as a constant pressure expansion valve.

This concept does not use a pin-four circuit, but uses the same refrigerant flow path, and when the valve body is closed as a temperature expansion valve, the main passage is conceptually used as a pin-yasu passage. This has the advantage of simplifying the system.

That is, when the evaporation temperature is high and the evaporation pressure is high, the pressure of the contents in the first control section A is higher than the pressure of the contents in the second control section B. This pressure is equal to the pressure below the diaphragm 22 and It competes with the bias spring and transmits a force effective for valve opening control to the diaphragm receiver 29 via the transmission means 28.

However, when the first control pressure decreases to a constant pressure, that is, a pressure lower than the pressure of the contents sealed in the second control part B, the first control pressure applies an effective force to the transmission means 28. Never.

It is the pressure of the second control part B that counteracts the combined force of the pressure on the lower side of the diaphragm 22 and the bias spring.

As a result, the relationship between the evaporation pressure of the refrigerant and the pressure of the drive unit is constant, including the adjustment by the bias spring for the evaporation temperature.At lower evaporation temperatures, the valve body opens regardless of the superheat degree signal. . There, the evaporator becomes a full liquid trap, reducing the evaporator's capacity and preventing freezing. Instead, liquid returns to the compressor. However, since the compressor used in a small simple refrigeration system that requires this system is usually of a rotary type, the liquid return is not an inconvenience for the compressor.

[Problem to be solved by the invention]

Although the above system appears to be effective in principle, there are various problems with its construction.

The first is that pressure transmission means 28 between the diaphragm 24 of the first control section B and the diaphragm 22 of the second control section B must be provided.

That is, in order to transmit the displacement of the diaphragm 24 to the displacement of the diaphragm 22, the pressure transmitting means must slide smoothly on the inner periphery of the outer shell 21 of the control section B without any gaps. In addition, in order to uniformly push down the diaphragm 22, the shape of the pressure transmitting means 28 is complicated because the contact part with the diaphragm must have a large diameter, and there is a requirement to accurately transmit the pressure of the control person. It will not appear unless the shape is precisely machined.

Second, the space for the sealed fluid in the control section B must be large enough that fluctuations due to changes in the volume of the control section A can be ignored. Conversely, the control section A is required to have a small space and a large diaphragm diameter in order to generate a sufficiently large force.

Thirdly, since two diaphragms are used, there is a lack of structural reliability due to the fact that there are two locations that require welding during manufacturing.

Basically, the present invention accomplishes this by pumping refrigerant into the evaporator more than necessary when the evaporation pressure and evaporation temperature are low to turn the evaporator into a droplet state without using the constant pressure expansion valve function as described above. The purpose is to preserve its normal function as a temperature expansion valve under normal conditions.

[Means to solve the problem]

In order to achieve the above object, in the present invention, under normal conditions, the valve opening degree of the thermal expansion valve is determined by the pressure of the gas enclosed in the power element (based on vapor-liquid equilibrium or adsorption equilibrium) and/or the pressure of the power element diaphragm. It is controlled by the pressure difference at the bottom (this pressure difference corresponds to the superheat degree signal), but when the liquid refrigerant passes through the passage formed by the valve body and valve seat, the pressure difference of the liquid refrigerant is large. Sometimes, that is, when the evaporation temperature of the refrigerant in the evaporator is lower than the evaporation temperature used to set the static superheat of the thermal expansion valve, the valve body receives the force of the fluid flow and adjusts the command valve opening according to the superheat signal. In order to obtain a sufficiently large valve opening, the diaphragm diameter (that is, determines the force that opens the valve) and the valve port diameter (determines the force that the valve body receives from the fluid flow and the refrigerant flow rate)
is selected according to equation (4), and the valve body is made into a conical shape.

(Formula A) ψ (δ, ΔP) bow (PH-PL) ((D12-D2)
−4CILD1sin2θ2)−(F,+,L)=0 Here, ψ(δ, ΔP) represents the force F1 of the diaphragm pushing the valve body. (F1=ψ(δ, ΔP)) That is, Fl is a function of ΔP obtained by converting the degree of superheat to pressure and the deflection δ of the diaphragm.

Dl is the diameter of the valve port OD, and D2 is the diameter of the cylindrical transmission rod DS that transmits the force F1 that pushes the valve body. [(When the transmission rod takes an h structure that is not significantly affected by the force of the refrigerant flow, set D2→0)] By D2→0, (P
In the flow direction shown in FIG. 1, the thrust force in the direction in which the valve body opens is the maximum.

PM is the saturation pressure at the condensation temperature of the refrigerant, PL is the saturation pressure at the evaporation temperature of the refrigerant, C1 is the flow coefficient, L is the distance the valve element moves when opening in the axial direction from the valve closing point, and K is the above. Fo is the coefficient for converting the force when the valve body moves by , Fo is the force of the superheat adjustment spring determined from the specifications at point H, θ1: includes the central axis of the cone with the apex angle MA of the upper part of the conical valve Half apex angle of the triangular cross section, θ2: Half apex angle of the outflow angle FA at the lower part of the conical valve body (same definition as θ1) With this configuration, when the degree of superheat is small in the low evaporation temperature range, is also a thermal expansion valve that supplies a certain amount of refrigerant to the evaporator.

Furthermore, by selecting the valve angle of the two-stage conical valve body at 02>θ1 (maximum effect when θ2 is −), it is possible to maintain the above-mentioned characteristics of the refrigerant in the low evaporation temperature range while maintaining an appropriate flow rate with respect to changes in the degree of superheating. This is a temperature expansion valve.

The present invention further incorporates the above technical concept into a thermal expansion valve and a refrigerant path so that a part of the valve is placed in the refrigerant path from the evaporator to the compressor, and the other part is placed in the refrigerant path from the condenser to the evaporator. This includes application to a structure in which the diaphragm diameter and valve/-) diameter of the temperature expansion valve to be integrated and the conical valve body shape are selected using 2A.

[Body 4-! )e-effect] The thermal expansion valve of the present invention operates as follows.

At the condensing and evaporating temperatures set as the standard design conditions, the valve lift characteristics and valve port diameter are determined based on formula AK so that the valve operates at a constant static superheat and operating superheat, so the signal from the temperature sensor The valve opening is obtained according to the pressure difference between the pressure inside the Δwar element and the pressure from the bottom of the diaphragm of the /4 war element (actually, the force of the bias spring is also included). The flow rate of refrigerant flowing into the evaporator is controlled based on the temperature signal.

However, in the temperature expansion valve of the present invention, the effective diameter of the diaphragm of the power element is adjusted so that when fluid flows at a pressure difference higher than a certain pressure, the power element applies force in the direction of opening the valve. The valve body is made into a conical valve and the apex angle of the cone is determined so that the port diameter is sufficiently large and the force generated by the fluid flow can be effectively utilized. Deviating from the lift (valve opening area) superheat characteristic, when the evaporation temperature or evaporation pressure is low, the valve remains open and refrigerant is supplied to the evaporator even if the superheat signal does not reach the static superheat. In other words, the force of the fluid flow acts on the valve element in the opening direction, adding a function of "opening the valve" that is not dependent on the superheat degree signal.

In addition, by providing an outflow angle FA on the refrigerant outflow side of the valve body,
By setting the half apex angle of 9FA to the half apex angle of VA such that θ2>θ1, it acts to reduce the value of aΔP in relation to the rate of increase in flow rate with respect to the change in superheating degree compared to the case of 02-01.

[Example 1] An embodiment of the present invention is shown in FIG.

Briefly referring to FIG. 1, the valve case 1 is provided above with an upper diaphragm chamber 3 and a lower diaphragm chamber 4, which are partitioned by a diaphragm 2. 5 is a capillary connected to a temperature-sensitive tube (not shown). Reference numeral 6 indicates a refrigerant inlet pipe, and 7 indicates a refrigerant outlet pipe. 8 has a transmission rod 9 fixed to the lower surface of the diaphragm 2 with a stopper. The refrigerant inlet pipe 6 and the outlet pipe 7 are connected by a valve port 10, and a conical valve body 12 is provided opposite a valve seat 11 provided at the valve port. However, in the illustrated case, the conical valve body is a two-stage valve body consisting of a high-pressure side valve body 121 and a low-pressure side valve body 12b. And each half apex angle is VA(θt) e F
A ('2) Show te. 13 is a spring that acts on the conical valve body. Further, 14 is an evaporation pressure intake port.

Although not shown in FIG. 1, a temperature sensing tube is provided which detects the temperature of the system refrigerant flowing at the evaporator outlet and outputs a pressure signal P above the diaphragm 2. The evaporation pressure PL is the pressure acting from the bottom of the diaphragm and is the pressure above P! The differential pressure with Δp is defined as Δp=p, -pL.

The force F1 by which the diaphragm pushes the valve body 12 can be approximated as a function of the differential pressure ΔP in the diaphragm chamber 4 and the deflection δ of the diaphragm. That is, F1 = ψ (δ, ΔP) ... (1) At this time, when the fluid, that is, liquid refrigerant flows through the flow path composed of the conical valve body and the valve seat l, the change in the thrust force F2 that acts on the conical valve body is as follows. It can be approximated as follows.

F2=-4・C1・LLID, asi(2・θ2)−
(Pl!-PL) ”・(2) Above (1) # (2)
The static equilibrium equation of the thermal expansion valve of the present invention can be obtained as follows using .

ψ(δ, ΔP) + 7(Pa PL) ((DI −
D2) 4CILD1sin2θ2)-(F0+,
L)=O...(3) (3) is the previously mentioned 2A.

The meanings of the symbols are as described above.

In this embodiment, D2→O, that is, when the cylindrical transmission rod that transmits the force of the diaphragm 2 does not appear in the refrigerant flow path (the configuration of the transmission rod is a bias spring that supports the valve body as shown at 30 in FIG. 14). K (corresponding to the case where it acts directly on) will be explained.

When the system refrigerant is R12, the temperature-sensitive cylinder-enclosed refrigerant RJj is used, and the condensation temperature is 50°C, 40°C, and 30°C, the valve diameter O
The diameter D1 of D is used as a gauge (in this case, the diaphragm is made of beryllium steel with a thickness of 0.10 and a diaphragm diameter of 22
■I am using one. ) Saturation pressure P at evaporation temperature
The relationship between L and refrigerant flow rate is illustrated in FIG. 7. In this embodiment, the value #1 of the first valve angle MA is set so that when the valve diameter OD is changed, the same opening area is obtained with respect to the movement distance LIC of the valve body in the valve opening direction at that OD. The static superheat degree is 1,800 kg when the temperature of the thermosensor is 0°C.
/cN12G, so it corresponds to 3.155.

The refrigerant flow rate in FIG. 7 is a calculated value corresponding to a superheat degree of 3.5K.

In conventional temperature expansion valves, when the refrigerant charged into the temperature sensing tube is the same as the system refrigerant, the degree of static superheat tends to increase in the low evaporation temperature range. Therefore, in FIG. 7, the behavior was similar to that when the valve diameter OD was 2-.

Naturally, the higher the condensation temperature, the higher the PIK, and therefore the higher the flow rate. In this embodiment, when the valve diameter is 5 or more, the flow rate increases as the evaporation temperature decreases at the same degree of superheat.

When the valve diameter is smaller than 4 dews, the flow rate tends to decrease as the evaporation temperature decreases. The valve diameter of the thermal expansion valve according to the present invention can be selected depending on the area of use and how much flow rate is expected in that area of use. To expect the valve to open at a superheat degree of 3.5 at a condensing temperature of 30℃ and an evaporation temperature of -20℃, assuming the other specifications above are constant, the OD must be 4.
It should be more than dew.

The above does not mention the influence of other conditions on static superheat. However, in an actual thermal expansion valve, as the valve diameter increases, it becomes more susceptible to the influence of the condensing temperature.

That is, the valve diameter is 00. PM and ψ(
δ, ΔP) ΔP is related to the travel distance LIC of the valve body in the axial direction from the valve closing point to the valve opening, as expected from the rewritten formula (3). It contributes to increasing L. Therefore, as the condensing temperature increases, the degree of superheating change becomes too large.

In order to suppress this, the value of the second term in the denominator of equation (4) may be increased. The second term in equation (4) is a term generated by providing the outflow angle FA shown in FIG. When the value of the second term becomes large, the above-mentioned increase in flow rate can be alleviated. This can be traced back to equation (3). / -4CI L Dlsia (2・θ2) (Pg-
The origin of PL) represents the amount of decrease in thrust load when the valve body is subjected to fluid in the valve opening direction.

This amount becomes maximum when the value of the outflow angle FA is θ2=45°. Therefore, when it is desired to increase this effect, it is desirable to select a value near 45° for θ2.

Figure 8 shows the change in the static superheat degree (defined as the static superheat degree in this example) at a valve opening of 0.01■ (near the valve closing point), with the first parameter being the wild condensation dermis. , (30° C., 40° C., so.degree. C.) A second flow rate of 2 meters is shown as the valve diameter. According to FIG. 8, it can be seen that when the condensing temperature is high and the valve diameter OD is too large, the static superheat degree changes significantly depending on the evaporation temperature.

On the other hand, FIG. 9 shows an embodiment in which the shift is suppressed by the second term of the denominator of the above equation (4). In the normal superheat degree refrigerant flow curve, the condensing temperature is used as a parameter and f lot is set, but the outflow angle θ2 (23,5 and the valve angle '+(
23, s°) are equal, the negative line outflow angle (45・s°) is equal to
) and the valve angle (23,5@), sb clearly shows the effect of the second term at -X-1. In other words, by setting the outflow angle, when the superheat degree change is small, the flow rate in the low evaporation temperature range secured by the valve diameter OD and the diameter Da of the pressure transmission element, which was not mentioned in this example, can be ensured. The flow rate can be suppressed when the superheat degree change is large, which would cause problems if only the selection of 00° DB was made.

[Example 2] In this example, other specifications are almost the same as in Example 1, but as shown in FIG. be influenced. Therefore, it is necessary to enter a specific value for 1)2GC of 2A (that is, (3)).

In this example, the valve diameter ODftD1-8m and 10
(2), and the diameter D2 of the shaft diameter DS of the operation transmission rod is selected so that the fluid pressure receiving area effect corresponding to the ODK of the first embodiment is almost equal to the effect of this embodiment.

That is, the valve diameter of Example 1 was set to 0.

When the valve diameter of this embodiment is Dl, D2 is D
When we set 2=Yahachikoden-, we chose KD2 so that the result of D2 would not be far different from the result when D2=O. In addition, as in the case of Example 1, the half apex angle θ of the apex angle MA of the conical valve body is
1.

Figure 10 shows the operating rod shaft diameter D2 when the valve diameter is 8 mm and the degree of superheat is 3.5, using the armature meters (5.81 m, 6.25 m, 6.61 m, 6.93 m, and 7.19 m). vm)
The relationship between the refrigerant flow rate and the evaporation temperature is plotted when the condensation concentration is 50°C, 40°C, and 30°C.

If we change the viewpoint and plot the relationship between the static superheat degree and the evaporation temperature when the valve opening degree is 0.01 m, we can see FIG. 11 when the valve diameter D1 is 8 mm. In both cases, the behavior is similar to that in Example 1, indicating that the technical concept of the present invention is valid even when the transmission rod newly appears in the refrigerant flow path as shown in FIG.

- In order to suppress the increase in flow rate even at the degree of superheating, K is possible by setting the outflow angle θ2 to 02>θ.D2#6
1a■ is shown. Both θ2>θ1 [Example 3
] What is the technical idea of the present invention using Figures 2 and 3? An example applied to a Tux type thermal expansion valve will be described.

The block case 300 has a liquid refrigerant inlet 301 that flows in from the condenser, a refrigerant outlet 302 that supplies refrigerant to the evaporator, an inlet 303 for refrigerant gas that exits the evaporator, and an outlet 304 for refrigerant gas that heads toward the compressor. . The arrows shown in the figure indicate the direction of flow of the refrigerant. In this embodiment, the block case is made of aluminum alloy material. Case lid part 3
05, an insertion hole 306 provided at the top of the block case 300 for housing a component that performs the function of a temperature expansion valve, which will be described later, is inserted into the QIJ ring 307 after the functional components are assembled. It is a lid for sealing. The parts housed in the block case that function as a temperature expansion valve are a power element part 308, a valve body 309 that integrates a force transmission part and a conical valve body, and a bias spring 310.
Consists of.・The heating element part 308 has activated carbon 312 sealed in a temperature-sensitive part formed by the heating element case six and the bottom plate 315, and further applies a constant pressure at a constant temperature through a thin tube 314 that will be sealed later. A gas with pressure-temperature adsorption characteristics is enclosed. In this example, R13 was encapsulated. In addition to adjusting the amount of activated carbon and placing the activated carbon in the refrigerant flow path, a wire mesh 313 was placed to prevent the gas communication port 318 provided in the center of the bottom plate 315 from being blocked by the activated carbon. Furthermore, a diaphragm 316 is arranged between the bottom plate 315 and the diaphragm receiver 317, and its peripheral edge is connected to the power element case 31.
1 and the periphery of the diaphragm receiver 317 using the diaphragm receiver 317, and seal the diaphragm receiver 317 airtightly using solder. The diaphragm 316 was made of perilicum steel with a thickness of 0.1 mm and an outer diameter of 22 m.

The diaphragm 316 has waves near its periphery so that a predetermined deflection can be obtained in response to changes in the pressure within the knocker element. The deflection δ of the diaphragm is determined by the pressure PL in the power element and the pressure PL applied to the lower surface of the diaphragm 316 through the pressure equalization hole 319 (this PL is the pressure of the refrigerant flowing from the refrigerant gas inlet SOS to the refrigerant gas outlet 304). The differential pressure ΔP can be t, b, δ and ΔP
The force F1 that pushes the valve body downward is determined from .

A bottom plate 315 is provided to limit upward deformation of the diaphragm 316. A stopper 320 is also provided to limit downward deformation.

The force F1 that pushes the valve body of the diaphragm is stop/#-320
It is transmitted to the valve body 309 via the e-collar 321.

The reason why the collar 321 is provided is to fix the bellows seal 322 to the valve body 309 so that the pressure equalizing chamber at the lower part of the diaphragm is not affected by the high-pressure liquid refrigerant flowing from the liquid refrigerant inlet 301. Integrated color 321. The functional part of the Perot seal 322 and the valve body is arranged in the central hollow part of the day 323 and is slidable.
23 intersects with the central hollow part and has a liquid refrigerant population of 30
A high pressure liquid inlet communicating with 1 is provided. Functional department again? The lower part of the day 323 has a lower hollow part 326 having a larger diameter than the central hollow part, and the lower part of the central hollow part has a valve/
- form a sheet 324; A bias coil spring 310 is disposed within the lower hollow part, and the bias spring force is adjusted by an adjustment screw 325.

In this embodiment, the valve port diameter is 6.3-. The apex angle of the conical valve body was set to a medium angle of 20°, but the outflow angle was 45°.
°. Further, the diameter of the lower hollow portion is 10.3-. (
(See Figure 3) In this embodiment, in the temperature expansion valve function part, the activated carbon enclosing part 312 of the nower element part 308 flows from the refrigerant gas inlet 303 to the refrigerant gas outlet 304 via the nower element case 311. Senses the temperature of the refrigerant.

This temperature corresponds to the superheated vapor temperature of the refrigerant, and the pressure corresponding to this temperature becomes the pressure P in the arm element due to adsorption equilibrium. - way p, PL=ΔP and Fl, which is related to the deflection δ of the diaphragm, acts as a force that pushes the valve body, so the valve opening degree is determined by the fluid force determined by the piascus and the shape of the valve.

In this manner, the flow rate of refrigerant from the liquid refrigerant inlet 301 to the refrigerant outlet 302 is controlled.

In this example, for comparison with the conical valve body shown in Fig. 3, a conical valve body was created in which the part corresponding to Fig. 3 was changed to that shown in Fig. 4.
A comparison was made with the case shown in the figure.

FIGS. 3 and 4 are explanatory diagrams in which the valve body 309 and the functional portion of FIG. 2 are enlarged views of the valve body 323.

In the case of a conical valve body without a separate outflow angle as shown in Figure 4, even if the condensing pressure is changed from oH7c,F to 15 kg/1ya2, the relationship between the evaporation pressure and Kerr valve stroke is almost the same as shown in Figure 6. constant. However, as shown in Fig. 3, if the outflow angle of one conical valve body is set to 02 = 45' so that the third term in the equation becomes maximum, the relationship between the evaporation pressure and Kerr valve stroke as shown in Fig. 5. When the condensing pressure is high, the absolute value of the gradient becomes small, and the tendency for the flow rate to flow more than necessary is suppressed.

〔Effect of the invention〕

According to the thermal expansion valve according to the present invention, it can be used in a refrigerant circuit and installed at the inlet of an evaporator in the same way as a conventional thermal expansion valve, and it can be installed without any additional elements in addition to the conventional thermal expansion valve. Under normal conditions, it functions as a temperature expansion valve based on conventional superheat control without adding any circuits or special parts, and in the low evaporation temperature range (i.e., low evaporation pressure range), it functions as a temperature expansion valve based on the above superheat control. In fact, even when the degree of static superheating has not been reached (the degree of superheating is small), the function of pumping refrigerant to the evaporator can be performed.

[Brief explanation of the drawing]

Fig. 1 is a schematic sectional view of one embodiment of the temperature expansion valve of the present invention, Fig. 2 is a longitudinal sectional view of another embodiment of the invention, and Fig. 3 is the valve body and valve port of Fig. 2. An enlarged view of the part, Figure 4 is a comparison sandal created to compare the characteristics of the configuration shown in Figure 3.
Fig. 5 is a graph showing the relationship between the evaporation pressure Kerr valve stroke showing the characteristics of the third embodiment, and Fig. 6 is an enlarged view of the valve body and the valve /-) part in Fig. g2. 4th valve port part
Figure 7 is a graph showing the relationship between the evaporation pressure Kerr valve and the four valves showing the characteristics when configured as shown in the figure. A graph showing the relationship between evaporation temperature and refrigerant flow rate using the diameter as a parameter. Figure 8 shows the characteristics of an embodiment of the thermal expansion valve of the present invention. Evaporation temperature when changing the condensing temperature and using the valve diameter as a parameter. - A graph showing the relationship between the static superheat degree and FIG. 9, which shows the relationship between the superheat degree and the refrigerant flow rate to explain the change in characteristics when an outflow angle is set in the conical valve body of an embodiment of the thermal expansion valve of the present invention. The graph shown in FIG. 10 is a graph corresponding to FIG. 7 of the second embodiment of the present invention (when DI=8m),
Figure 1 shows the second embodiment of the present invention (when D1=8 gourds)
12 is a graph corresponding to FIG. 9 of the second embodiment of the present invention (when DI=8ms+), and FIG. 13 is a graph of a refrigeration system used for air conditioning. The configuration diagram, FIG. 14, is a longitudinal sectional view of an expansion valve that integrates a conventional constant pressure expansion valve and a temperature expansion valve. 2...Diaphragm, O...Valve I-to, 2...Valve body O

Claims (5)

[Claims] (1) Temperature expansion in which the valve opening degree is controlled by a superheat degree signal in order to increase the efficiency of the evaporator installed in a heat exchange system that uses a refrigerant whose main components are a compressor, condenser, evaporator, and expansion mechanism. In a valve, when the pressure difference between the upstream side where refrigerant flows and the downstream side of the valve body that combines with the valve seat is larger than the pressure difference that was used as a reference when setting the static superheat degree of the thermal expansion valve, the actual superheat degree is determined. Pushes the valve body, which is a function of the superheat degree signal and the amount of deflection of the diaphragm of the power element of the expansion valve, so that a refrigerant flow rate above a certain amount can be supplied to the evaporator even if the signal falls below the set static superheat degree. In addition to this force, the diaphragm diameter and valve port diameter are selected so that the fluid adds a force that pushes the valve body in the direction of flow, and the shape of the valve body is conical to reduce the additional restraining force due to the fluid flow. A temperature expansion valve characterized in that it is used. (2) In the valve body shape of the conical valve body, the valve angle near where the refrigerant flow outflows to the low pressure side is set to be larger than the valve angle near where the refrigerant flow flows in from the high pressure side. 2. The thermal expansion valve according to claim 1, wherein the temperature expansion valve is a two-stage conical valve body. (3) In order to increase the efficiency of the evaporator installed in a heat exchange system using a refrigerant whose main components are a compressor, a condenser, and an expansion mechanism, high pressure In order to avoid the influence of the refrigerant flowing into the temperature expansion valve from the side on the force pushing the valve body, the valve body is connected to a force transmission rod that transmits the pushing force from the power element to the valve body, so that the fluid flows into the valve body. It has a mechanism that offsets the force applied in the pushing direction, and the valve body is shaped like a conical valve body, and the opening degree of the valve near the outflow of the refrigerant flow to the low pressure side is adjusted to the vicinity of the inflow of the refrigerant flow from the high pressure side. A temperature expansion valve characterized by having a two-stage conical valve body having a valve angle larger than the valve opening degree. (4) A first flow path that communicates with the condenser; a second flow path that communicates with the evaporator through the first flow path and a valve chamber having a valve seat; a block case having a third flow path provided through the evaporator and communicating with the evaporator; a fourth flow path communicating with the third flow path through the temperature-sensitive working chamber and communicating with the compressor; An enclosure formed by a power element case and a diaphragm is installed in the temperature-sensitive operating chamber and whose pressure changes in response to changes in the temperature of the refrigerant passing through the third flow path and the fourth flow path. a temperature-sensing section sealed in a chamber; a conical valve body having a transmission rod that transmits displacement to the valve body by the operation of the diaphragm; and a conical valve body facing a valve seat provided in the valve body; In a thermal expansion valve consisting of a spring that constantly biases the body toward the valve seat, the pressure difference between the upstream side of the valve body that engages the valve seat and the downstream side of the valve body through which refrigerant flows sets the static superheat degree of the thermal expansion valve. When the pressure difference becomes larger than the reference value, the superheat degree signal and the expansion valve are adjusted so that a refrigerant flow rate of a certain amount or more can be supplied to the evaporator even if the actual superheat degree signal becomes less than the set static superheat degree. The diaphragm diameter and valve port diameter are selected so as to add a force pushing the valve disc in the direction of fluid flow to the force pushing the valve disc, which is a function of the amount of deflection of the diaphragm of the power element. A temperature expansion valve characterized by having a conical valve body shape and utilizing an additional restraining force due to fluid flow. (5) In the valve body shape of the conical valve body, the valve angle near where the refrigerant flow flows out to the low pressure side is determined to be larger than the valve angle near where the refrigerant flow flows in from the high pressure side. The temperature expansion valve according to claim 4, characterized in that it is a stepped conical valve body.